Method for making stators for electric motors and the like

ABSTRACT

The axial end portions of the insulating members which are used to line the longitudinal channels formed between circumferentially adjacent, radially inwardly projecting poles in a stator (e.g., an electric motor stator) are protected from damage by the wire being wound by providing terminal boards at each axial end of the stator having portions which overhang the axial ends of the insulating members. Temporary wire grippers may also or alternatively be mounted on the axial ends of the stator (e.g., on the above-mentioned terminal boards) for temporarily holding the leads of the stator coils prior to permanent termination of those leads on permanent terminals on the terminal boards.

This is a continuation of application Ser. No. 07/628,476, filed Dec.17, 1990 now U.S. Pat. No. 4,099,568, which is a division of applicationSer. No. 07/385,570, field Jul. 26, 1989 now U.S. Pat. No. 4,994,697.

BACKGROUND OF THE INVENTION

This invention relates to methods and apparatus for making stators forelectric motors and similar machines such as generators. Although theinvention is described herein in the context of its application ofelectric motor stators, it will be understood that it is equallyapplicable to other types of stators such as have been mentioned.

Terminals boards for electric motor stators are insulating members whichare typically placed on both axial ends of the main stator body for suchpurposes as supporting the axial ends of the windings wound on the polesof the stator and providing insulated attachment points for theterminals at which the ends of the coil wires can be connected to wiresexternal to the stator.

Recently there has been increasing interest in winding stators withoutwinding forms (see, for example, Wheeler U.S. Pat. No. 4,612,702). Thiscan simplify the winding apparatus and speed the winding process, but itcan also increase the strain and wear on the insulting inserts which aretypically placed in the stator between circumferentially adjacent polesin order to prevent short circuits between the coils and the stator.Such strain and wear can compromise the insulating effectiveness of theinsulating member, possibly resulting in short circuits to the stator.Dislocation or distortion of the insulating member may also occur,possibly resulting in vibration or interference with free rotation ofthe armature in the finished motor.

In view of the foregoing, it is an object of this invention to providestator making methods and apparatus, and especially terminal boards,which better protect the associated insulating inserts, especiallyduring winding without winding forms, but even when winding forms areused, if desired.

Another problem which may be exacerbated when winding without windingforms is the possibility that some winding turns in the axial ends ofthe coils, and especially those winding turns which are intended to fillthe area close to the axial end of the stator and in the radiallyoutermost portion of the coil, may not be sufficiently tight or closetogether to preclude undesirable vibration of those winding turns duringoperation of the finished motor.

It is therefore another object of this invention to provide statormaking methods and apparatus, and especially terminal boards, whichpromote tight, regular, and complete winding and filling of the statorcoils, especially during winding without winding forms, but also whenwinding forms are used, if desired.

In some electric motor stators the ends of the coil wires (i.e., theso-called start and finish leads) are anchored directly in the terminalreceptacles on the terminal board (see, for example, Pearsall U.S. Pat.No. 4,074,418). Metal terminals are then pushed into the receptacles tomake electrical contact with the coil wires. In other motors, however,the ends of the coil wires must be held temporarily during and afterwinding. At a subsequent termination station the ends of the coil wiresare relocated to terminals mounted on the terminal board. In the past,the elements for temporarily holding the ends of the coil wires havebeen provided on the pallets or other structures which support and/orconvey the stators (see, for example, Wheeler U.S. Pat. No. 4,612,6702,Nussbaumer et al. U.S. Pat. No. 4,679,312, and Santandrea et al. U.S.Pat. No. 4,713,883). Providing elements for temporarily holding the endsof the wire coils on the pallet or other coil supporting structure(hereinafter referred to generically as a pallet) has a number ofdisadvantages. For one thing, these wire-holding elements complicate thepallet, thereby increasing its costs. The presence of these wire-holdingelements around the stator also make it more difficult to place thestator on or remove the stator from the pallet. The stator-handlingelements which perform these tasks must be designed so that they do notinterfere with the wire-holding elements. The need for wire-holdingelements on the pallet may make it difficult or impossible to use thesame pallet for stators of different size (e.g., different stackheight). A substantial amount of wire may be needed to temporarily reachwire-holding elements on the pallet. This wire may have to be cut offand discarded when the wire is finally permanently terminated on theterminal board. The fact that the coil ends are temporarily attached tothe pallet may make it more difficult or impossible to use certainpermanent termination techniques which would otherwise be advantageous.For example, it may be difficult or impossible to employ permanenttermination apparatus which requires removal of the stator from thepallet.

In view of considerations such as the foregoing, it is still anotherobject of this invention to provide improved methods and apparatus fortemporarily holding the ends of coil wires during and after winding thecoils on the poles of a stator.

SUMMARY OF THE INVENTION

These and other objects of the invention are accomplished in accordancewith the principles of the invention by providing a terminal boardhaving a lip or bead which projects out over the axial end of theinsulating member which lines the channel between circumferentiallyadjacent poles of a stator. This lip or bead performs such functions asprotecting the end of the insulating member, preventing the insulatingmember from shifting axially relative to the stator, and ensuring thatthe wire being wound bears on the terminal board and not on the morefragile axial end of the insulating member as the wire is drawn aroundthe poles of the stator. This lip or bead also promotes depositing theaxial ends of the coils close to the axial ends of the stator, therebyimproving the tightness, regularity, density, and efficiency of thecoils. The foregoing features are especially useful when winding statorswithout winding forms, although they may also be useful even whenwinding forms are employed.

The stators (preferably the terminal boards) of this invention may alsohave grippers for temporarily holding the ends of the coil wires so thatthese ends can be subsequently picked up and relocated to terminalspermanently mounted on the terminal board. This has a great manyadvantages including facilitating processing of stators on and offpallets, simplifying the design of the apparatus which must handle thestator after winding but before the coils are permanently terminated,facilitating the design of apparatus which can handle stators ofdifferent sizes (e.g., different stack heights), and reducing wireconsumption.

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an axial end view of an illustrative embodiment of a statorconstructed in accordance with the principles of this invention prior towinding coils on the stator poles.

FIG. 2 is a partial sectional view taken along the line 2--2 in FIG. 1.

FIG. 3a is a view similar to FIG. 2, but showing a prior art structure.

FIG. 3b is a partial perspective view of a prior art stator structure.

FIG. 4 is a partial sectional view taken along the line 4--4 in FIG. 1.

FIG. 5 is a partial sectional view taken along the line 5--5 in FIG. 4.

FIG. 6 is an enlargement of a portion of FIG. 1.

FIG. 7 is a detail view taken alone the line 7--7 in FIG. 6.

FIG. 8 is an elevational view of an alternative embodiment of apparatusconstructed in accordance with this invention.

FIG. 9 is a view taken along the line 9--9 in FIG. 8

FIG. 10 is a partly sectional view of a stator constructed in accordancewith this invention mounted on a pallet.

FIG. 11 is a partly sectional view of a stator constructed in accordancewith this invention mounted in an alternative way on an alternativepallet.

FIG. 12 is a sectional view taken along the line 12--12 in FIG. 11.

FIG. 13 is a flow chart of stator making methods in accordance with thisinvention. FIG. 13 is also a schematic block diagram of stator makingapparatus in accordance with this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a terminal board 20 constructed in accordance with thisinvention and mounted on an axial end of a stator 10. Terminal board 20is a complete annular ring, although it could also be made up of two ormore semiannularly (meaning partly annular) segments. Behind terminalboard 20 in FIG. 1 is the stack of metal laminations 12 (see FIG. 2)which forms the main body of the stator. Terminal board 20 itself istypically made of an insulating material such as plastic. Terminal board20 typically includes terminal receptacles (e.g., receptacles 22a-d), atleast some of which hold or will receive metal terminals (e.g., terminal50 in FIG. 2) to which the ends of the stator coil wires are attached tofacilitate making electrical connections to the stator. (The terminalreceptacles 22 shown in the drawings are for terminals of the type whichare generally inserted when the stator is in the termination stationafter the coils have been wound. The depicted terminals 50, on the otherhand, are of a type which are generally inserted before the terminalboard is applied to the stator. These two different types of apparatusare depicted merely to make it clear that the present invention can beused in either case.)

In the depicted illustrative embodiment, stator 10 has two poles 14a and14b, although it could have more poles if desired. In front of each pole14 terminal board 20 has a coil holder 24a, 24b which extends axiallyoutward from the portion of the terminal board which is adjacent to thesurface of the pole that is concentric with central longitudinal axis16. At the axial end of each coil holder 24 which is remote from themain annular portion of terminal board 20 each coil holder has a coilretainer tab 26a, 26b which projects radially outward from theassociated coil holder.

Before terminal board 20 is mounted on stator stack 12, an insulatingmember, insert, or liner 30a, 30b is pushed axially into each channelwhich exists between circumferentially adjacent stator poles. Eachinsert 30 is preferably axially somewhat longer than the stator stack(excluding terminal boards 20) so that each insert projects slightlyfrom each axial end of the stator stack prior to attachment of terminalboards 20. After inserts 30 are in place, a terminal board 20 is mountedon each axial end of the stator stack as shown in FIGS. 1 and 2.

As can be seen in FIG. 1, the main annular portion of terminal board 20has generally the same shape and extent as the associated axial end ofstator stack 12 except for a lip or bead 40 which projects over andtherefore covers the axial end of the adjacent insert 30 (see also FIG.2). The prior situation without this bead is illustrated by FIG. 3a (inwhich the reference numbers 20 and 24 are used merely to help the readeridentify generally corresponding parts of the structure and not to meanthat the FIG. 2 structure forms part of the present invention). Inaccordance with this invention, lip or bead 40 protects the axial endsof inserts 30 during winding of the coils on poles 14, especially whenthese coils are wound without winding forms. In particular, it has beenfound that when the stator is wound without terminal boards having lipor bead 40 (e.g., terminal boards as shown in FIG. 3a), the wireemerging, for example, from region A tends to hit the axial end portionof the adjacent insert 30 which is radially outward from region A.(Arrows 32 show the direction of motion of the needles which wind thewire in this example.) This hitting of insert 30 can have severalundesirable results. For example, it can corrugate the insert (due tothe wire sliding or running on the exposed surface of the inset),causing the material of the inset to displace at other locations (e.g.,in region C where the inset may bulge radially inwardly so that it canvibrate against the stator stack when the finished motor is operated orso that the insert interferes with rotation of the armature). Hitting ofthe insert can also break through the inset, with the possible loss ofinsulation between the coil and the stator stack. The portion of lip orbead 40 which is radially outward from region A protects this part ofthe axial end of insert 30 and thereby eliminates or at least greatlyreduces the foregoing possible problems.

This portion of lip or bead 40, as well as other portions of the lip orbead in the vicinity of region A, also provides a smooth surface (whichis typically harder than insert 30) on which the wire can more readilymove or run in the circumferential direction as the end of thewire-winding needle (not shown) passes over the top (or bottom) ofretainer tab 26 in order to pull the windings tightly around the poles.By facilitating the circumferential movement of coil wires duringwinding in this manner, lip or bead 40 may also improve the resultingcoils, for example, by helping the coils to wind more tightly,regularly, and densely about the poles and by reducing the possibilitythat voids will form in the coil, especially close to the axial end ofthe stator, as the winding proceeds.

On the other side of each pole 14, as the wire being wound re-enters thestator (e.g., adjacent region B), the wire must bend generally aboutedge B and may also need to move along edge B. Once again, the presenceof lip or bead 40 overhanging and thereby protecting the axial end ofinset 30 prevents the wire from damaging the insert, with possible lossof insulation between the coil and the stator stack, Lip or bead 40 inregion B also ensures that the wire contacts a smooth, hard surfacewhich facilitates motion of the wire along edge B. As in the case of theportion of the lip or bead 40 in the vicinity of region A, this may helpproduce better windings by increasing the tightness, regularity,density, and completeness of the coils.

Another advantage of lip or bead 40 on the terminal boards at both endsof the stator stack is that these lips or beads held to hold inserts 30in their proper axial positions in the stator and reduce the risk thatan inset may be dislocated by handling of the stator or before enoughwindings have been applied to permanently retain the inserts. Small,localized clips 34 (FIG. 3b) have been used in the past to help holdinsert 30 in place both axially and radially. But structures likecontinuous lip or bead 40, with all the additional advantages describedabove, were unknown prior this invention.

Note that (as shown in FIG. 2) in order to prevent coil holders 24 frombecoming too thick as a result of the need to provide the adjacentportion of lip or bead 40, that portion of terminal board 20 is thickerin the radial direction than either the portion which is immediatelyadjacent the stator stack or the portion which forms coil holder 24. Thetransition from coil holder 24 to this thicker portion is preferablyinclined as shown at 42 in FIGS. 2 and 5. This incline promotes runningof wire being wound toward the adjacent stator pole, which tends toimprove the coil sin the ways that have been mentioned above. Also notethat the bead surface 44 on the other side of the channel depicted inFIG. 2 is preferably inclined relative to both the longitudinal axis ofthe stator and the axial end face of the stator so that surface 42 and44 are synclinal in the direction into the stator.

If desired, wire grippers 90 can be mounted on one or both axial ends ofthe stator (e.g., by being mounted on one or both of terminal boards 20as shown in FIGS. 1 and 6) for temporarily holding a coil lead prior topermanent termination of that lead on the terminal 50 in an adjacentterminal receptacle 22. Grippers 90 can be at any convenient locationson ends of the stator or the associated terminal boards 20. After thestator has been wound, it is typically passed form the winding stationto a terminating station. In the terminating station, each coil lead isremoved from its gripper 90 and permanently terminated on a terminal 50in a terminal receptacle 22.

Although various gripper constructions can be used, FIGS. 1, 6, and 7show one illustrative form of gripper 90 which is integral with terminalboard 20. Gripper 90 has two upstanding members 92 and 94 with a slot 96therebetween. The smallest portion of slot 96 is narrower than thediameter of the wire lead 72 to be held in gripper 90. Accordingly, wirelead 72 can be pushed down into slot 96 which then holds the lead untilit is subsequently lifted out and relocated to a terminal 50 in anadjacent terminal receptacle 22.

The number of grippers 90 will typically correspond to the number ofleads to be temporarily held, although additional grippers 90 may beprovided in the event that a lead is to be temporarily anchored in afirst gripper, then relocated to one or more other grippers before beingfinally terminated on a terminal 50. Note that some motors are made withmore than one coil per pole, and/or with coils having intermediate taps.Grippers 90 can be used for the start, intermediate (if any), andfinished leads of each coil.

If desired, after they have performed their temporary wire-holdingfunction, grippers 90 can be knocked off or otherwise removed from thestator. For example, FIGS. 8 and 9 show an alternative gripper 190 whichis not integral with terminal board 20. Instead, gripper 190 is aseparate element which can be plugged into a simple hole in terminal 20(or stator body 12 if the gripper is at a location not covered byterminal board 20) by means of pin 198. As in the case of gripper 90, awire lead can be temporarily held in slot 196 between upstanding members192 and 194. At the appropriate time, the wire lead can be removed fromslot 196 and permanently secured to a terminal 50. Thereafter, gripper190 can be removed from the stator (e.g., by pulling pin 198 out of theassociated terminal board hole or by shearing gripper 190 off above pin198).

The placement of grippers 90 or 190 (hereinafter referred to genericallyas grippers 90) on stator stack 12 or terminal board 20 rather than onthe pallet or other apparatus which holds the stator during processinghas several important advantages. For example, FIG. 10 shows stator 10being transported vertically on pallet 120 having pin 122, centralcolumn 124, and peg 126 for positioning the pallet with the requiredprecision. In FIG. 10 coils 70 have been wound on the stator, leads 72are temporarily secured in grippers 90, and terminals 50 are in placebut not yet connected to wire leads 72. Accordingly, FIG. 10 showsstator 10 as it might be conveyed on pallet 120 from a coil windingstation to a lead terminating station.

Because leads 72 are held in grippers 90 on the stator rather than inelements mounted on pallet 120, stator 10 can be readily placed on orremoved from pallet 120 at either or both of the winding and leadterminating station. The area around the stator is not cluttered bylead-holding elements, thereby simplifying the design of the apparatusrequired to remove the stator 10 from pallet 120 or to place the statorback on the pallet. The amount of lead wire required to reach thewire-holding elements is also reduced by having the elements (i.e.,grippers 90) right on the stator. And if it is desired to processstators (e.g., stators 10') of a different size (e.g., a different stackheight ), no changes or considerably fewer charges are required topallet 120 than if wire leads 72 were held by elements on the pallet.FIGS. 11 and 12 show that similar advantages obtain when stator 10 istransported horizontally on pallet 120'. Such horizontal transport maybe advantageous in certain situations (e.g., when leads are to beterminated at both ends of the stator).

As has bee mentioned, FIG. 13 is a flow chart of the stator makingmethods of this invention. FIG. 13 is also a block diagram of the statormaking apparatus of this invention. In step or station 100 stator stackor body 12 is provided in any conventional manner. In step or station102 insulating members 30 are inserted in the longitudinal channelswhich are present in the stator between circumferentially adjacentpoles. This step or station can also be conventional (see, for example,Luciani et al. U.S. Pat. No. 4,831,716 which shows suitable apparatus ofthis kind). In step or station 104 terminal boards 20 are attached tothe axial ends of the stator body in any conventional manner. One orboth of these terminal boards may include wire grippers 90.Alternatively, wire grippers 90 may be mounted directly on stator body12 in step or station 104.

In step or station 106 coils are wound on the stator poles. Luciani etal. U.S. patent application Ser. No. 321,919, filed Mar. 13, 1989, showsapparatus suitable for manipulating the start and finish leads of statorcoils. This or other known apparatus can be readily adapted to depositthe start and/or finish leads of the coils in wire gripper 90 ifdesired. (Of course, if wire grippers 90 are not needed and the startand finish leads can be anchored directly in terminal receptacles 22,then other known apparatus such as that shown in Pearsall U.S. Pat. No.4,074,018 can be used in step or station 106 for handling the start andfinish leads.) Various known coil winding needle structures and motionscan be used to actually wind the coils in step or station 106 (see, forexample, Wheeler U.S. Pat. No. 4,612,702 and Luciani U.S. Pat. No.4,762,283 which show suitable needle structures and motions).

Following step or station 106, the stator is typically moved from thewinding station to a terminating station 108 where the state and finishleads are terminated or where the termination of those leads iscompleted. For example, if the start and finish leads have been anchoreddirectly in terminal receptacles 22 as in Pearsall U.S. Pat. No.4,074,418, then in step or station 108 a metal terminal is typicallypushed into each terminal receptacle in the known manner to make contactwith and complete the termination of each lead. On the other hand, ifthe coil leads are being temporarily held by wire grippers 90, then instep or station 108 each such lead is removed from its wire gripper andtransferred to the appropriate permanent metal terminal. The knownapparatus for transferring such leads from the wire grippers on palletsor other stator holding apparatus to permanent terminals as in WheelerU.S. Pat. No. 4,612,702, Nussbaumer et al. U.S. Pat. No. 4,679,312, andSantandrea et al. U.S. Pat. No. 4,713,883 can be readily modified totransfer leads from wire grippers 90 to permanent terminals 50. Notethat the principle disclosed in Santandrea et al. U.S. Pat. No.4,713,883 of winding and terminating the stator on the pallet can beused with this invention if desired.

If wire grippers 90 have been used, and if it is desired that they notremain on the finished stator, then in step or station 110 wire grippers90 may be removed by any suitable technique such as by shearing them offor by pulling them out if they are plugged into the stator.

It will be understood that the foregoing is merely illustrative of theprinciples of this invention and that various modifications can be madeby those skilled in the art without departing from the scope and spiritof the invention. For example, wire grippers 90 can be mounted directlyon stator stack or body 12 or can be mounted on terminal boards 20 asexplained above.

I claim:
 1. The method of making a stator comprises the stepsof:providing a hollow annular stator body having a longitudinal axis anda plurality of radially inwardly projecting poles, circumferentiallyadjacent poles defining a longitudinal channel therebetween; lining thesurface of said channel with an insulating member; mounting a terminalboard on each axial end of said stator body, each terminal board havinga major plane which is substantially perpendicular to said longitudinalaxis when said terminal board is mounted on said stator body, a portionof said terminal board overhanging the adjacent axial end of saidinsulator member to cover the axial end of said insulator member,wherein the longest dimension of said overhanging portion is parallel tosaid major plane; and winding a coil of wire around each pole.
 2. Themethod of making a stator comprising the steps of:providing a hollowannular stator body having a plurality of radially inwardly projectingpoles, circumferentially adjacent poles defining a longitudinal channeltherebetween; lining the surface of said channel with an insulatingmember; mounting a terminal board on each axial end of said stator bodyso that a portion of said terminal board overhangs the adjacent axialend of said insulator member; winding a coil of wire around each pole;and depositing said wire so that a portion of said wire rests on saidoverhanging portion of said terminal board after winding, whereby saidoverhanging portion functions as a barrier between said wound wire andsaid axial end of said insulator member.
 3. The method of making astator comprising the steps of:providing a hollow annular stator bodyhaving a longitudinal axis, first and second axial ends, and a pluralityof radially inwardly projecting poles, circumferentially adjacent polesdefining a longitudinal channel therebetween, each said pole having afirst longitudinal side and a second longitudinal side; lining thesurface of each said channel with an insulating member; mounting aterminal board on each axial end of said stator body so that a portionof said terminal board overhangs the adjacent axial end of saidinsulator member, the length of said over-hanging portion beingperpendicular to said longitudinal axis; winding a coil of wire aroundeach pole by repeatedly translationally depositing said wire on one ofsaid first and second sides of each said pole and circumferentiallyextending said wire outside said stator body and across said terminalboard to reach the other of said first and second sides of said pole;and running said wire on said overhanging portion of said terminal boardduring translational movement of said wire until said wire comes to restso that said wire is prevented from running on the axial edge of saidinsulating member, wherein the orientation of said wire changes fromsubstantially parallel to said overhanging portion to substantiallyperpendicular to said overhanging portion while running along saidoverhanging portion.